In writing 'Celluloid Skyline', James Sanders had contributed one of the more interesting texts about the city in recent years. He'd been working on the book for 12 years, and it showed. As his site puts it, it was about two cities, both called New York – one is the physical city, and the other is imagined New York in film. The book is essentially a contribution to urban theory – it has that depth – but by drawing from '42nd Street', 'Taxi Driver', 'North by Northwest' and 'Big', it was also accessible, riveting. Sanders had recently revisited the material of the book to construct an exhibition on 'Celluloid Skyline', which is currently running at Grand Central Station. There, the book comes alive, as projections of actuality films stand alongside giant scenic backings from studios, surrounding a series of excellent explanatory boards (designed by Lisa Strausfield's team at Pentagram). Sanders is a practising architect, as well as a writer.

For his talk at Postopolis!, Sanders did something that few other speakers did, which was to engage directly with the name, and perhaps theme, of the show. By thinking through the word 'postopolis', Sanders concentrated on "the city after", or what might be "post-city". And for his case study, selected for Postopolis!, he attempted to talk about depictions of the contemporary city. But not using a "high art film –like Tati or something", but a contemporary film. In this case the animated feature 'Shark Tale'.

Sanders then plays us 2 clips from 'Shark Tale', featuring the underwater cityscape mis-en-scene of the movie, and then talks us through the salient points as he sees them. The first – you can see a QuickTime clip here – inadvertently picks up on the previous panel's discussion of 'expressions of urban fear', by illustrating a near-dystopian, empty grey cityscape suddenly come alive with the news that 'the sharks are gone', presented by news reporter, Katie Current (Couric), broadcasting live from downtown. The city in 'Shark Tale' is clearly New York, with "a great central urban space ... modeled on Times Square" (though bits of LA are thrown in.)

As he points out, "the city is already underwater", predicting perhaps the inconvenient truth about downtown Manhattan in a few years. As the previously empty city explodes with life, Sanders runs through the "rich mix of things you'd see in the city". He says we see garbage collection, a form of urban grid, fish taxi drivers (which have some kind of South Asian heritage), Jamaican, Japanese etc. A richly diverse mix of fish, in fact, conjuring "the classic late capitalist city". This is a city, he says, whose urban life is saturated with electronics, and therefore images of, well, urban life. This self-referential aspect will become a central theme of Sanders' talk.

Once the news that 'the sharks are gone' filters through, Sanders says the city itself is essentially a "vibrant positive place". He suggests you "wouldn't have shown New York City in the same way, 20 years ago", which in some ways reinforces this idea that 'the city is back'. However, there is also this clear pervasive threat, from without. No prizes for guessing the symbolism here.

So we have the successful late capitalist city, though threatened from forces unseen outside. The city is a colourful diverse mix of ethnicity and possibility. Digital screens are everywhere.

The second clip exemplifies this last point, playing out a fight scene from later in the movie. In this, we see multiple, complex, textured conflation of image and reality. The central characters fall and swerve in front of screens, which show images of themselves in real-time, which they react to, and this – their reaction to seeing themselves broadcast – is then filmed and re-broadcast. This is a densely layered city, in which they're "interacting with their own televised image".

Sanders pauses to note a difference here. In the history of the city up to the 1950s, the 'agora' was shifting out of the centre, being dispersed. Now with real-time electronic newsgathering and the advent of large scale electronic displays in urban environments, Sanders says we're seeing a form of agora reborn. Bizarrely 'Shark Tale' shows a new hybrid – a new kind of space, which is urban and electronic at the same time, real-time and broadcast entwined symbiotically.

Of course, Times Square used to have a giant news ticker years ago, but there is a difference in immediacy here; this is news being made in real-time and then broadcast in real time. There's some element of 9/11 shifting things here; on that day, people stopped and watched live feeds of the towers, even those a few blocks uptown.

'Shark Tale' is also to do with the "push towards celebrity". It's everything to do with a media-saturated culture, in which the characters want to be famous most of all. And this is actually why, Sanders reckons, that the city is back. A celebrity is an urban phenomenon. The central character in 'Shark Tale', voiced by Will Smith, has all the ambition of the newcomer to the city, familiar from a thousand previous films, yet desires fame most of all. That's the way to the top. "Could've been a contender" is very clearly now "I want to be somebody".

It's a fascinating exploration of the themes implicit within the film's urban environment. Sanders suggests that this is actually the first mainstream depiction of this new kind of hyper-media-saturated city, with real-time broadcasting of the city woven into the city itself. This actually makes 'Shark Tale' significant (if it was largely insignificant in every other way.) These lmost subconscious renderings by designers and directors comprise a form of code for understanding contemporary urban life. This is the reason he thinks films are such valuable texts about the city.

In terms of whether 'Shark Tale's' city is genuinely the first mainstream depiction of a new kind of city, Geoff makes a strong counterpoint: that architecture has always contained embedded narratives – and narrative potential – about the city, but Sanders thinks that the immediacy and real-time reaction of this hybridised physical-digital space is something new, and 'Shark Tale' is exploring just that.

He suggests that designers and architects could learn a lot from the practice of production designers. I ask him about this; about what architects and designers could draw from film-making. His answer is fascinating; he explains that production designers are always building an architecture to be inhabited by a narrative, which means people (99.9% of the time.) There are effectively no films about buildings i.e. without people. Certainly no popular films. There are numerous films made about streets, cities etc. but all as the backdrop for people and stories. Geoff wonders about the 'haunted house' genre, and whether the buildings play a leading role here. Sanders counters that if Jodie Foster didn't show up in 'Panic Room' fairly soon, there wouldn't have been much of a film. So his key point is that the production designers who create the buildings, streets and other built fabric for movies are actually working in a way which engages inhabitants more directly than many architects. Indeed, he points, it's only relatively recenlty that architectural phtography in magazines started having people in shot. He suggests architects prefer their buildings empty, unused. (Ironic that Andrew Blum's talk had preceded, noting how Libeskind's museums are often initially empty.)

Sanders' talk, and his Celluloid Skyline projects, approach architecture and urbanism from the periphery of their depiction in films, and this makes for compelling viewing and listening. If you're in New York, do try to get to the exhibition (Celluloid Skyline, Vanderbilt Hall, Grand Central Station, until June 22nd.)

In writing 'Celluloid Skyline', James Sanders had contributed one of the more interesting texts about the city in recent years. He'd been working on the book for 12 years, and it showed. As his site puts it, it was about two cities, both called New York – one is the physical city, and the other is imagined New York in film. The book is essentially a contribution to urban theory – it has that depth – but by drawing from '42nd Street', 'Taxi Driver', 'North by Northwest' and 'Big', it was also accessible, riveting. Sanders had recently revisited the material of the book to construct an exhibition on 'Celluloid Skyline', which is currently running at Grand Central Station. There, the book comes alive, as projections of actuality films stand alongside giant scenic backings from studios, surrounding a series of excellent explanatory boards (designed by Lisa Strausfield's team at Pentagram). Sanders is a practising architect, as well as a writer.

For his talk at Postopolis!, Sanders did something that few other speakers did, which was to engage directly with the name, and perhaps theme, of the show. By thinking through the word 'postopolis', Sanders concentrated on "the city after", or what might be "post-city". And for his case study, selected for Postopolis!, he attempted to talk about depictions of the contemporary city. But not using a "high art film –like Tati or something", but a contemporary film. In this case the animated feature 'Shark Tale'.

Sanders then plays us 2 clips from 'Shark Tale', featuring the underwater cityscape mis-en-scene of the movie, and then talks us through the salient points as he sees them. The first – you can see a QuickTime clip here – inadvertently picks up on the previous panel's discussion of 'expressions of urban fear', by illustrating a near-dystopian, empty grey cityscape suddenly come alive with the news that 'the sharks are gone', presented by news reporter, Katie Current (Couric), broadcasting live from downtown. The city in 'Shark Tale' is clearly New York, with "a great central urban space ... modeled on Times Square" (though bits of LA are thrown in.)

As he points out, "the city is already underwater", predicting perhaps the inconvenient truth about downtown Manhattan in a few years. As the previously empty city explodes with life, Sanders runs through the "rich mix of things you'd see in the city". He says we see garbage collection, a form of urban grid, fish taxi drivers (which have some kind of South Asian heritage), Jamaican, Japanese etc. A richly diverse mix of fish, in fact, conjuring "the classic late capitalist city". This is a city, he says, whose urban life is saturated with electronics, and therefore images of, well, urban life. This self-referential aspect will become a central theme of Sanders' talk.

Once the news that 'the sharks are gone' filters through, Sanders says the city itself is essentially a "vibrant positive place". He suggests you "wouldn't have shown New York City in the same way, 20 years ago", which in some ways reinforces this idea that 'the city is back'. However, there is also this clear pervasive threat, from without. No prizes for guessing the symbolism here.

So we have the successful late capitalist city, though threatened from forces unseen outside. The city is a colourful diverse mix of ethnicity and possibility. Digital screens are everywhere.

The second clip exemplifies this last point, playing out a fight scene from later in the movie. In this, we see multiple, complex, textured conflation of image and reality. The central characters fall and swerve in front of screens, which show images of themselves in real-time, which they react to, and this – their reaction to seeing themselves broadcast – is then filmed and re-broadcast. This is a densely layered city, in which they're "interacting with their own televised image".

Sanders pauses to note a difference here. In the history of the city up to the 1950s, the 'agora' was shifting out of the centre, being dispersed. Now with real-time electronic newsgathering and the advent of large scale electronic displays in urban environments, Sanders says we're seeing a form of agora reborn. Bizarrely 'Shark Tale' shows a new hybrid – a new kind of space, which is urban and electronic at the same time, real-time and broadcast entwined symbiotically.

Of course, Times Square used to have a giant news ticker years ago, but there is a difference in immediacy here; this is news being made in real-time and then broadcast in real time. There's some element of 9/11 shifting things here; on that day, people stopped and watched live feeds of the towers, even those a few blocks uptown.

'Shark Tale' is also to do with the "push towards celebrity". It's everything to do with a media-saturated culture, in which the characters want to be famous most of all. And this is actually why, Sanders reckons, that the city is back. A celebrity is an urban phenomenon. The central character in 'Shark Tale', voiced by Will Smith, has all the ambition of the newcomer to the city, familiar from a thousand previous films, yet desires fame most of all. That's the way to the top. "Could've been a contender" is very clearly now "I want to be somebody".

It's a fascinating exploration of the themes implicit within the film's urban environment. Sanders suggests that this is actually the first mainstream depiction of this new kind of hyper-media-saturated city, with real-time broadcasting of the city woven into the city itself. This actually makes 'Shark Tale' significant (if it was largely insignificant in every other way.) These lmost subconscious renderings by designers and directors comprise a form of code for understanding contemporary urban life. This is the reason he thinks films are such valuable texts about the city.

In terms of whether 'Shark Tale's' city is genuinely the first mainstream depiction of a new kind of city, Geoff makes a strong counterpoint: that architecture has always contained embedded narratives – and narrative potential – about the city, but Sanders thinks that the immediacy and real-time reaction of this hybridised physical-digital space is something new, and 'Shark Tale' is exploring just that.

He suggests that designers and architects could learn a lot from the practice of production designers. I ask him about this; about what architects and designers could draw from film-making. His answer is fascinating; he explains that production designers are always building an architecture to be inhabited by a narrative, which means people (99.9% of the time.) There are effectively no films about buildings i.e. without people. Certainly no popular films. There are numerous films made about streets, cities etc. but all as the backdrop for people and stories. Geoff wonders about the 'haunted house' genre, and whether the buildings play a leading role here. Sanders counters that if Jodie Foster didn't show up in 'Panic Room' fairly soon, there wouldn't have been much of a film. So his key point is that the production designers who create the buildings, streets and other built fabric for movies are actually working in a way which engages inhabitants more directly than many architects. Indeed, he points, it's only relatively recenlty that architectural phtography in magazines started having people in shot. He suggests architects prefer their buildings empty, unused. (Ironic that Andrew Blum's talk had preceded, noting how Libeskind's museums are often initially empty.)

Sanders' talk, and his Celluloid Skyline projects, approach architecture and urbanism from the periphery of their depiction in films, and this makes for compelling viewing and listening. If you're in New York, do try to get to the exhibition (Celluloid Skyline, Vanderbilt Hall, Grand Central Station, until June 22nd.)